Method of improving the color of a petroleum resin by hydrofining



METHOD OF IMPROVING THE (TOLOR OF A PETROLEUM RESIN BY HYDROFINING Maurice K. Rausch, Harvey, Ill., assignor to Sinclair Refining Company, New York, N.Y., a corporation of Maine 7 No Drawing. Application December 21, 1955 Serial No. 554,425

2 Claims. (Cl. 208-45) My invention relates to a method for the improvement of aromatic fractions which are derived from heavy petroleum fractions.

It is known to prepare aromatic fractions from heavy petroleum fractions in a variety of ways by the appropriate treatment of heavy petroleum residues or distillates and lubricating oil stocks obtained from naphthenic or asphalt based crudes or mixed, i.e., Mid-Continent, base crudes. The aromatic fractions ccntain the aromatic constituents of the crude oil with a minimum of parafiinic, naphthenic and asphaltic materials. The aromatic fractions can be derived by the solvent, e.g., phenol, furfural, nitrobenzene and so forth, extraction of heavy bright 2,931,766 Patented Apr. 5, 1960 2 various embodiments falling Within the scope of my invention and are to be considered not limitative.

EXAMPLE I Mid-Continent heavy reduced crude having an API gravity-of 15.5", a Saybolt Universal viscosity at 210 F. of '1023, a' carbon residue (con.) of 11.1 and a. sulfur content of 0.91 percent by weight is first deasphalted in a stocks having a viscosity of more than about 100 Saybolt Universal seconds at 210 F.; by propane or butane fractionation of the lubricating oil extracts obtainzd from conventional solvent treating of bright stock lubricating oils; by vacuum distillation of the lubricating oil extracts obtained from solvent treating lubricating oils; or by chromatographic separation of heavy petroleum distillates and residuals using alumina, clay or similar earths as the adsorbent. The aromatic fractions can also be obtained using the process described in Hunn application, Serial No. 288,135, filed May 16, 1952 (now US. Patent 2,727,847, dated December 20, 1955), in which a deasphalted residual stock is treated with a selective solvent which has a high selectivity for aromatic components to separate a raw resinous fraction and in which such raw resinous fraction is fractionated at a temperature of about 100 F. to 200 F. with liquid propane, following which there are recovered a high viscosity aromatic resin from the propane insoluble phase and a deresined extract oil from the propane soluble phase. The aromatic fractions are characterized by an API gravity below about 15.0 and a viscosity of about 400 to 15,000 SUS at 210 F.

The aromatic fractions are useful for a variety of purposes, for example, as ingredients in sound-deadening compositions, of adhesive compositions, of protective coatings, as tile and rubber plasticizers or as paper laminates. There is aneed, however, for a process whereby the color and color stability of such aromatic fractions is improved without substantial loss of the fractions and 7 the aromatic fraction to a mild hydrogenation or hydrofinishing operation. The following examples illustrate tower at a top tower temperature of F., a bottom tower temperature of 125 F. and a pressure of 475 p.s.i.g. employing a propane to oil ratio of 9:1 by volume. Following this, the reduced crude is extracted in a tower having a top tower temperature of F. and a bottom tower temperature of 200 F. and using a phenol to oil ratio of 1.75:1. The phenol used is aqueous phenol containing 5 ercent by weight of water. By this operation there is produced an aromatic fraction charge stock which has the caracteristics set forth in Table I.

This charge stock is hydrofinished employing a Va inch pelleted catalyst comprising cobalt-molybdate supported on alumina having the following analysis: cobalt oxide, 2.88 weight percent; molybdic oxide, 10.3 weight percent; silica, 5.2 weight percent; and the balance alumina. This catalyst, before use in the treatment of the aromatic fraction charge stock in the presence of hydrogen, is pretreated for 2 hours with hydrogen at 700 F. and atmospheric pressure followed by pretreatment with hydrogen sulfide at 700 F. and atmospheric pressure for 2 hours. In the hydrofinishing operation, the temperature employed is 700 F., the pressure employed is 450 p.s.i.g., the weight hourly space velocity is 3 and the hydrogen recycle ratio is 1500 standard cubic feet per barrel. After the hydrofinishing, the aromatic fraction is given a light steam stripping at 350 F. to remove dissolved water, dissolved hydrogen sulfide and any light cracked products produced by the hydrofinishing. The stripped, hydrofinished aromatic fraction is designated hydrofinished product 1 (after stripping) and has the characteristics set forth in Table I.

It is seen that tl.e color improvement is from 1276 CD. for the charge to 737 DD. for the hydrofinished product. Color stability, as measured by ultraviolet fadeometer stability test, is also measurably improved. The effect on aromaticity as measured by aniline point is not great, the aniline point elevation being 1.6 C. Thus, it is evident that considerable improvement in color and color stability were obtained with little decrease in desirable aromaticity properties. Both color and aromaticity are of importance in applications of the aromatic fractions as tile plasticizers and so forth.

Table I also sets forth data for another experiment in which the same hydrofinishing charge stock is empolyed with the same catalyst but in which the weight hourly space velocity is reduced to 0.5. It will be noted that the characteristics of the hydrofinished product (product 2) are similar, taking into account that no drastic hydrofinishingv conditions were employed. The flash point and viscosity of the hydrofinished product are somewhat lower, but one can resort to the topping oflf of a small amount of cracked materials to provide a product having a flash point and viscosity substantially the same as that of the charge. The effect of the hydro- .stripping at 350 F. to remove dissolved water and byproved color with little or no loss in aromaticity.

aasmee genation on ,Rostler analysis (molecular type) is very slight.

Table II HYDROFINISHING OF HEAVY AROMATIC RESIN Table I Hydrofin- Hydrofin- Hydrofin- Hydrofin- Charge lshed ished Charge lshei lshed Stock Pro uct 1 Pr u t 2 Stock Product 1 Product 2 (After (After (After (After Stripping) Stripping) Stripping) Stripping) Hydrofinlshing Conditions: fl d finl hing Conditions:

Temperature, "F 00 700. Te nperature F 700 700. Pressure, p.s.i.g 450 450. Pressure, p.s.i.g 450 450. WHSV a 0.5. Wt-ISV 3-.-. 0.5. Hydrogen Recyclc, 1,500 1,500. Hydrogen Reeyc1e,s.c.f./b.

sci/b. Hydrotinishing Yield, Vol. Hydrofinishlng Yield, Approx. 100- Approx. 100- 5 percent. Vol. percent. Laboratory Tests: Laboratory Tests: Gra I Gravity, APL. Flas Flash. F. Fire, ,0 Fire, F Viscosity, b at 175 F 35,100... V y, SUS at Viscosity, SUS at 210 5,600---. 4,370 2,90 NPA Color (30:1 Benzene Darin... 8- 8-. Viscosity, SUS at 210 Dilution).

F. NPA Color (00:1 Benzene 8- 6- G- Ponr,F 90 95 5- Dilution). Color, NPA Dark Green. Dark Green. Dark Green. 00191 01) 10,057-.. 6,476 0,923. Color Stability (OD) 1,275-1A81.-. 737-991 740-972. Ca bon Residue (Com), .1 12.6 .9. -.Color, OD; 1,276 737 740. percent,

Car u u (00 5.02 Mixed Aniline Point, C- 35.2 30.2 34.5. percent. Anilire Point, C 58 4 Iodine Number" (0 Sulfur, percent 1.0 0 1 Ultraviolet Color Stability Standard.- Various modifications can be made 1D the procedures 'Zlest. Bower Rubber Plasticizer v of the specific examples to provide other embodiments Analysis: WhlCh fall within the scope of my invention. Thus, al-

PerteutNitrogen Bases. 10.3 15.6. Percent Group I Um 1M though in those examples ahydrofimshing temperature of saturates. 700 F. and a hydrofinishmg pressure or 450 p.s.1.g. were igfig g f II employed, both the temperature and pressure can be Percent saturates 16.7 17.0. varied considerably. Generally, however, the hydrofinishing temperature used will be Within the range from On 50-50 blend 01 sample and titanium dioxide exposed in ultra about 500 to 800 F. and the pressure Will be within vlolet Fade-O-lv eter for 3 hours at 110 F the range from about 200 to 1000 p.s.1.g. The weight hourly space velocity will generally be within the range from 0.5 to 10 and the hydrogen recycle ratio will gen- EXAMPLE H erally be within the range to 200 to 10,000 standard A raw resin fraction is produced by the phenol extraction of propane deasphalted Mid-Continent heavy reduced crude, as described in Patent No. 2,727,847. This raw resin fraction is then contacted in a countercurrent extraction tower with commercial propane at a propane to raw resin ratio of approximately 9.521, at a top tower temperature of approximately 140 F., at a bottom tower temperature of approximately 120 F. and under sufficient pressure to maintain the propane in a liquid state (about 460 p.s.i.g.). The resulting two phases are separated and stripped free of solvent. By utilizing this procedure there is produced an aromatic resin charge stock having the characteristics set forth in Table II.

This aromatic resin fraction is hydrofinished employing the catalyst composition described in Example I'and employing a temperature of 700 F., a pressure of 450 p.s.i.g., a weight hourly space velocity of 3 and a hydrogen recycle ratio of 1500 standard cubic feet per ba-rrel. The hydrofinished product is given a light steam .drogen sulfide and any light cracked products. The stripped, hydrofinished aromatic resin is designated bydrofinished product 1 (after stripping) and has the characteristics set forth in Table II. I

It will be noted that color improvement is from 10,057 0D. to 6476 OD. The N.P.A. color at 30:1 dilution changes from dark to 8 and at :1 dilution from 8- The hydrofinished product shows no-increase in aniline point, so that it has the desirable feature of im- T able II also sets forth data which are obtained using the same charge stock and catalyst but employing a weight hourly space velocity of 0.5. It will be noted that the results are similar, taking into account the fact that no drastic hydrofinishing conditions are employed.

cubic feet per barrel of aromatic fraction.

Any of the catalysts conventionally employed in the hydrogenation of heavy petroleum oils can be utilized in accordance with the presentprocess. Examples of suitable catalytic ingredients are molybdenum, tungsten, vanadium, chromium, cobalt, nickel, iron and tin and their oxides and sulfides. Mixtures of these materials or compounds of two or more of the oxides can be employed. For example, mixtures or compounds of the iron group metal oxides or sulfides with the oxides or sulfides of group VI left column of the Periodic Table constitute very satisfactory catalysts. Examples of such mixtures 'or compounds are nickel molybdate, tungstate or chromate (or thiomolybdate, thiotungstate or thiochromate) or mixtures of nickel oxide with molybdenum, tungsten or chromium oxides. As the art is aware and as the specific examples illustrate, these catalytic ingredients are generally employed while disposed upon a suitable carrier of the solid refractory type.

I claim:

1. A method for producing aromatic resinous fractions of improved color and color stability without substantially decreasing the aromaticity of said fractions which comprises propane deasphalting a heavy asphaltic petroleum residual, solvent extracting the deasphalted residual with a solvent having a selectivity for aromatics to obtain an aromatic resinous fraction having an API gravity below about 15.0 and a viscosity of about 400 to 15,000 SUS at 210 F., passing said aromatic fraction in admixture with hydrogen into contact with a hydrogenation catalyst under a temperature from about 500 to within the range of about 200 to 10,000 standard cubic ee p r r el.

7 v 6 2. The method of claim 1 wherein the hydrogenation 2,417,308 Lee Mar. 11, 1947 catalyst is cob-alt molybdate supported on alumina. 2,706,167 Harper et a1. Apr. 12, 1955 2,717,864 Charlet et a1 Sept. 13, 1955 References Cited in the file of this patent 2,733,189 Gilbert et a1 Jan. 31, 1956 UNITED STATES PATENTS 5 2,394,751 Cole Feb. 12, 1946 

1. A METHOD FOR PRODUCING AROMATIC RESINOUS FRACTIONS OF IMPROVED COLOR AND COLOR STABILITY WITHOUT SUBSTANTIALLY DECREASING THE AROMATICITY OF SAID FRACTIONS WHICH COMPRISES PROPANE DEASPHALTING A HEAVY ASPHALTIC PETROLEUM RESIDUAL, SOLVENT EXTRACTING THE DEASPHALTED RESIDUAL WITH A SOLVENT HAVING A SELECTIVITY FOR AROMATICS TO OBTAIN AN AROMATIC RESINOUS FRACTION HAVING AN API GRAVITY BELOW ABOUT 15.0 AND A VISCOSITY OF ABOUT 400 TO 15,000 SUS AT 210*F., PASSING SAID AROMATIC FRACTION IN ADMIXTURE WITH HYDROGEN INTO CONTACT WITH A HYDROGENATION CATALYST UNDER A TEMPERATURE FROM ABOUT 500* TO 800*F., A PRESSURE WITHIN THE RANGE OF ABOUT 200 TO 1000 P.S.I.G., A WEIGHT HOURLY SPACE VELOCITY WITHIN THE RANGE OF ABOUT 0.5 TO 10 AND EMPLOYING A HYDROGEN RECYCLE RATIO WITHIN THE RANGE OF ABOUT 200 TO 10,000 STANDARD CUBIC FEET PER BARREL. 